Joseph g



(No'ModeL) J. C. GITHENS.

' RQTATORY FEED FOR STEAM ROCK DRILLS. No. 312,347. Patented Feb. 17, 1885.

Nirn rates ATENT rrrcnr JOSEPH C. GITHENS, OF NEIV YORK, N. Y., ASSIGNOR TO THE BAND DRILL COMPANY, OF SAME PLACE.

ROTATORY FEED FOR STEAM ROCK-DRILLS.

SPECIFICATION forming part of Letters Patent No. 312,3, dated February 1'7, 1885.

Application filed May .2, 1834.

T aZZ whom it may concern.-

Be it known that I, Josnrrr O. GrrrrnNs, of the city and State of New York, have invented a certain Improvement in Rolling Stops for Governing the Botatory Feed of Steam Rock-Drills and Analogous Engines, of which the following is a specification.

This improvement is a modification of that described in my pending application for a [O patent serially numbered 118,180, filed January 21, 1884, in which is described the employment of rollers, which are interposed between the wall of a chamber formed in the head of the steam-cylinder and the bottom of a notch formed in a wheel or hub affixed to the end of the spiral bar which extends into the cylinder and enters the longitudinal recess formed in the piston, and imparts the rotatory feed to the piston by being held stationary o during-the return-stroke of the piston, the rotatory set being imparted to the spiral bar during the working-stroke of the piston.

In order to avoid loss of time in effecting the movement of the cylindrical stops from 2 the wider parts of the recesses in which they are deposited to those parts of the recesses at which they bring up, expanding springs are employed, tending to press the rolling stops toward the narrower parts of the recesses.

The conditions precedent to the operation of the rolling stops are that there shall be a want of parallelism between the opposite side walls of the recesses in which the rollers are deposited, so that the turning of the spiral 5 bar during the working-stroke of thepiston would have the effect of causing the rolling stops to roll toward the wider parts of the recesses in which they are deposited, while dur ing the return-stroke of the piston the tend- 0 ency of the spiral bar to turn in the opposite direction will so act upon the rollers as to cause them to roll toward the narrower parts of the recesses in which they are respectively deposited, by which tendency therollers are 5 made to jam between the perimeter of the head of the spiral bar which constitutes one wall of the recess in which they are deposited and the opposite portion of the surface of the. chamber in the head of the cylinder which constitutes the other wall of the recess. In order to keep the rollers in position to (No model.)

jam instantly upon the commencement of the working-stroke ot' the piston, an expanding spiral spring is employed for each roller, which tends to press it toward the narrower part of its recess, and thus hold it in contact with the wall of the chamber in the cylinder on one side and the periphery of the head ot the spiral bar on the other side. When the spiral bar is rotated during the return-stroke of the piston, these springs yield, and thus allow the. rollers to move a sufficient distance toward the wider ends of their recesses and release the head of the spiral bar from friction.

In the structure shown in my application serially numbered 118,180 the necessary tapering or want of parallelism of the opposed side walls of the recesses in which the rollers are deposited is obtained by making the bottoms of the notches in the head of the spiral 70, bar eccentric with relation to the circular wall of the chamber in the head of the cylinder in which the head or wheel on the end of the v spiral bar is contained.

The modification which forms the subject of 7 5 my present invention consists in the employment of the cylindrical head of the spiral bar in combination with rollers contained in recesses formed in the side wall of the chamher in the head of the cylinder, the bottoms 83 of such recesses being eccentric with relation to the periphery of the head of the spiral bar.

In the structure shown in my application No. 118,180 the eccentric bearing for the roll- 8 5 ing stop was convex. In the present case the eccentric hearing, as will be seen, is concave, the concentric bearing being the periphery of the head of the spiral bar.

As the construction of rock-drills and analoo gous engines of the general character of that to which my present invention relates is Well known, I do not deem it necessary to describe such construction in detail.

The accompanying drawing represents a 5 transverse section of the hub of a rock-drill cylinder containingmy invention. The head of the cylinder A has cast upon it the usual ear, B, provided with the hole I), to receive the screw for eii'ccting the longitudinal adjustroo ment of the cylinder, and with the ears 0 and 1), provided with the holes 0 and d, respectively, for the reception of the bolts by which the heads of the cylinder are secured in position. The spiral bar E is keyed to or formed in one piece with the wheel or head F, which is contained in the usual chamber, G, formed in the head of the cylinder. The bottom of this chamber is centrally perforated, as usual, for the admission of the spiral bar. In the wall of the chamber formed in the head of the cylinder are provided a suit-able number of recesses, G, the bottoms g of which are, as will be seen, eccentric with relation to the periphery of the head F. The cylindrical rollers or rolling stops H are deposited, respectively, in the recesses G, and, as shown, are of slightly less diameter than the widest portion of those recesses. The rollers are pressed toward the narrower parts of those spaces by the expanding spiral springs h, which are contained in suitable recesses formed in the head of the cylinder, and exert their expanding thrust upon the rollers H, respectively, thus tending to hold the rollers against 'the periphery of the head I By a consideration of the drawing it will be seen that if the spiral bar E turns in the direction indicated by the arrow motions will be imparted to the rollers H tending to roll them toward the wider parts of the space in which they are contained and to compress the expanding springs h. It will also be understood that the extent of this rolling motion of the rollers H will be just suflieient to cause them to release their grip upon the head F. and that. as soon as there is any tendency of 3 the spiral bar E to rotate'in the opposite direction such tendency would tend to cause the rollers H to roll toward the narrower parts of their recesses, and will hence cause them to instantly jam toward the eccentric wall G of 40 the recess and the periphery f of the head F. This organization subserves the same purpose as the organization shown in my application No. 118,180-that is, the extent of the rotatory feed of the piston is definitely varied after different working-strokes proportionately to any variations which there may have been in the length of such working-strokes.

I claim as my invention- In mechanism for effecting the rotatory feed of the piston in the cylinder of a steam rock-v drill or other analogous engine, the side wall of the chamber formed in the head of the steam-cylinder, and provided with the concave recesses G, having their bottoms g ec- 5 centric with the periphery of the spiral bar, in combination with the rollers H. and the head F of the spiral bar E, and the piston I, substantially as and for the purpose set forth.

JOSEPH C. GITHENS.

\Vitnesses:

It. (J. HoWEs, M. L. ADAMS. 

